The present invention relates generally to a closed material handling transport system having a cable with disc-like members rigidly affixed thereto and disposed inside of a tube. Movement of the cable through the tube moves the material to be handled through the tube since the material is trapped between the discs and the tube. The present invention relates more particularly to a drive apparatus for adjusting for varying lengths of cable for such a closed conveying system.
One of the most critical problems in a material handling system of the general type referred to above is the one of keeping the proper amount of tension upon the cable, since if the cable is too tight or too loose, it can cause a malfunction of the system or possibly damage the equipment. One of the methods used for making this required adjustment in the past has been to lengthen or shorten the tube containing the cable to thereby adjust the tension on the cable. This has been done by putting in a proper length of tubing to lengthen the tube or taking out the proper length of tubing to shorten the tube. In doing this, either the cable must be taken apart, since it is a continuous cable, or an insert tube must be used which has an opening in the side thereof which allows the cable to be placed therein and which then allows for a closing of the insert tube side opening.
Another highly effective mechanism for providing this needed adjustment without the problems discussed above with respect to lengthening or shortening the conveyor tube to achieve the proper tension, is shown in U.S. Pat. No. 3,905,473. While the device shown in U.S. Pat. No. 3,905,473 is almost completely trouble-free and fool-proof, still there is a significant amount of expense in the construction thereof as compared to the invention described below.